The Office subscription will allow you to use the software on up to five devices. So, if you need multiple copies, the subscription could be a very good deal. Plus, you'll always have access to the latest versions of the software.
I like the subscription model for software.
I recently purchased a subscription to Adobe's products. It allows me to use their products on two computers. I had purchased two of their programs and the cost of upgrading those two would have been the same as paying for the subscription for a year. With the subscription, however, I am able to use many more of Adobe's products.